#include <stdio.h>

int main() 
{
    int a = 0;
    int b = 0;
    int c = 0;
    int d = 0;
    scanf("%d %d %d %d",&a,&b,&c,&d);

    float Score = a * 0.2 + b * 0.1 + c * 0.2 + d * 0.5;
    printf("%.1f",Score);
    return 0;
}